The recent urban recreational and industrial developments of coastal mangrove areas within numerous parts of the world have posed a threat on such important ecosystems. Bioaccumulation of anthropogenic chemicals and non-essential nutrients through the food chain has recently become a matter of concern for several researchers. Heavy metals like lead, cadmium, chromium and zinc are highly toxic pollutants which could be significantly associated with bioaccumulation within a myriad of ecological systems because they cannot be biologically degraded and instead get concentrated within sediments. Globally, there has been a unanimous agreement that the reported levels of heavy metals within mangrove sediments are increasing every year as a result of pollution and activities caused by developmental growth and urbanization. Although there are variations in the levels of heavy metal tolerance exhibited by different types of mangroves, the grey mangrove Avicennia marina has a relatively higher tolerance level when compared with other mangrove species. This quality qualifies grey mangrove to be a good bioindicator and enables researchers to obtain quantitative information about the environmental/ecological quality of its habitat through monitoring and experimental testing. It is speculated that Avicennia marina could be more tolerant to heavy metal by developing several adaption mechanisms including avoiding the uptake of metals actively and exclusion of ions. Numerous studies have utilized mangrove species and their sediments as reliable bio-indicators for heavy metal pollution and contamination. Interestingly, the bio-concentration of various metals in this plant differs according to the type of tissue. For instance mangrove leaves tend to accumulate lower levels of metals as compared with mangrove roots and sediments. It has been reported that very low heavy metal concentrations accumulated in leaf tissues because most absorbed heavy metals accumulated in stem and root tissue. Nevertheless, root tissue is the most commonly used bioindicator for heavy metal pollution with high reliability and accuracy as compared to leaves.Journal impact factor is an index or a criteria devised by Eugene Garfield to categorize journals based on their citations. Impact factor is considered as a putative marker to indicate the journal quality. But the recent policies being adopted to improve the impact factor is becoming a topic of controversies today. This current scenario questions the reliability of impact factor. The citation index cannot be considered to determine the scientific quality of an article because the technicalities are not considering the scientific quality. Knowing or reading an article is not enough to determine their quality validating the content and approving the findings and revalidating the facts is vital in scientific research. It is highly impossible to do a scholar check in each and every article to detect fraudulent or unsubstantial citations.
Last date updated on June, 2014